Electrifying the sea?

[Yai]

If you took some cables, connected one end to the national grid and the other end to a big lake or the sea, would the all the fish in the lake be electrocuted? Would the current spread to all the oceans in the world and kill all the whales and fish? Would metal boats blow up? If not, why not?

[CleverClogs]

Even though its called the national grid it is seperated into lots of area seperated grids. Which are all seperately protected from overloads. Which is exactly what would happen if you placed a HV cable into the sea. More likely the cable would melt or the power station would shut down......... Back to your lab, you are definately the mad scientist type dude.........

[norfolk boy]

try it and carry out an earth loop impedance test on the cable !

[wrighty1980]

The sea would not conduct electricity because it is salty. Fresh water would conduct electricity, but the damage it would do would depend on whether the subjct were 'earthed' or not. I think boats would be okay, in the same way that birds can safely sit on an electrified wire.

[trilobite]

Lots of issues here. But I'm afraid you're wrong, wrighty1980. Absolutely pure water does NOT (at least in theory) conduct electricity. Addition of impurities eg sodium chloride (salt) forms an electrolytic solution and increases the conductivity. Therefore seawater would conduct electricity very well.

Assuming the 'National Grid' does not 'shut down', the effect (risk of electrocution) of this much 'electricity' would be extremely localised in the grand scheme of things (ie due to the sheer volume of the oceans)

[norfolk boy]

Did you also know that pure water will not conduct electric.Apparently only impurities in water will allow it to conduct.

[norfolk boy]

Hey Trilobite you got the smartie pants answer in before me!!!

[jenstar]

Hang on, this can't be right, surely? If I read those answers correctly, then to blow out the local grid all you would have to do is run a live cable down to the sea and plug the other end in at the mains. That sounds bizarre. Would a river or pond do just as well?

[trilobite]

Errr.... not quite, jenstar. All that would do is blow a fuse wherever it's plugged in. We're talking about multi-power station outputs here at 240 000 Volts (not the 240V in your home) and assuming we could link all power stations together to one big output cable.